Document Detail


Model of pulmonary fluid traffic homeostasis based on respiratory cycle pressure, bidirectional bronchiolo-pulmonar shunting and water evaporation.
MedLine Citation:
PMID:  20153588     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The main puzzle of the pulmonary circulation is how the alveolar spaces remain dry over a wide range of pulmonary vascular pressures and blood flows. Although normal hydrostatic pressure in pulmonary capillaries is probably always below 10 mmHg, well bellow plasma colloid pressure of 25 mmHg, most textbooks state that some fluid filtration through capillary walls does occur, while the increased lymph drainage prevents alveolar fluid accumulation. The lack of a measurable pressure drop along pulmonary capillaries makes the classic description of Starling forces unsuitable to the low pressure, low resistance pulmonary circulation. Here presented model of pulmonary fluid traffic describes lungs as a matrix of small vascular units, each consisting of alveoli whose capillaries are anastomotically linked to the bronchiolar capillaries perfused by a single bronchiolar arteriole. It proposes that filtration and absorption in pulmonary and in bronchiolar capillaries happen as alternating periods of low and of increased perfusion pressures. The model is based on three levels of filtration control: short filtration phases due to respiratory cycle of the whole lung are modulated by bidirectional bronchiolo-pulmonar shunting independently in each small vascular unit, while fluid evaporation from alveolar groups further tunes local filtration. These mechanisms are used to describe a self-sustaining regulator that allows optimal fluid traffic in different settings. The proposed concept is used to describe development of pulmonary edema in several clinical entities (exercise in wet or dry climate, left heart failure, people who rapidly move to high altitudes, acute cyanide and carbon monoxide poisoning, large pulmonary embolisms).
Authors:
Sven Kurbel; Beatrica Kurbel; Danijela Gulam; Borislav Spajić
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-02-12
Journal Detail:
Title:  Medical hypotheses     Volume:  74     ISSN:  1532-2777     ISO Abbreviation:  Med. Hypotheses     Publication Date:  2010 Jun 
Date Detail:
Created Date:  2010-04-14     Completed Date:  2010-07-29     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7505668     Medline TA:  Med Hypotheses     Country:  United States    
Other Details:
Languages:  eng     Pagination:  993-9     Citation Subset:  IM    
Copyright Information:
.
Affiliation:
Department of Physiology, Osijek Medical Faculty, Osijek, Croatia. sven@jware.hr
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MeSH Terms
Descriptor/Qualifier:
Blood Pressure
Bronchioles / blood supply,  physiology
Extracellular Fluid / physiology
Homeostasis
Humans
Hydrostatic Pressure
Lymphatic System / physiology
Models, Biological*
Pulmonary Alveoli / blood supply,  physiology
Pulmonary Circulation / physiology
Pulmonary Edema / etiology,  physiopathology
Respiratory Physiological Processes*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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